This invention relates to the field of flexible jaw couplings. More particularly, this invention relates to an elastic annular component for providing an elastic connection between opposed halves of a flexible jaw coupling.
One known type of annular elastic component for jaw couplings comprises a ring of spaced molded blocks with bridging pieces alternately connecting each two adjacent blocks. One form of such annular elastic component is shown and described in U.S. Pat. No. 3,924,419. In order to simplify initial assembly of a flexible coupling incorporating one of these annular elastic components, or in order to shorten the inoperative period of machinery when changing the annular elastic component, the trend in the industry has been to form the annular component as a single molded piece with the individual blocks being connected by the bridging pieces which preferably consist of the same material as the blocks. For any given coupling it is, of course, most desirable to design the annular elastic component, in terms of construction and material, to achieve maximum length of operating time for that coupling. There are, however, limits as to the material which can be used for the annular elastic component, since compromises must be made between the elastic properties, the wear resistance properties and thermal stability. Duration tests on test rigs have shown that even slight structural alterations can make significant differences in durability of the annular elastic component. Attempts have been made, particularly with regard to the design of the connecting or bridging components between the individual shaped blocks, to attain higher wear resistance for the overall annular elastic component.
It is also known that unacceptable heating, resulting from extreme shape alterations of the component parts, can lead to rapid wear and even destruction of the annular elastic component. A particular cause of such heating is the result of axial movements, radial movements, and angling of the halves of the entire coupling relative to one another, which movements can never be entirely eliminated.
Other factors, such as friction forces and resilience or restoring forces must also be taken into consideration. On the one hand, friction between the annular elastic component and the side faces of the dog or teeth of the coupling halves, which can result from rolling movement of the individual shaped blocks on those side faces, may not exceed a predetermined value. On the other hand, the annular elastic component must have a predetermined amount of resilience or restoring force. That is, the individual parts of the annular component should not perform the rolling movement too easily, because torque transmission is never continuous, but has increasing and decreasing characteristics, particularly when transmitting intermittent forces. This results in periodic alteration, of varying frequency, of the force being transmitted. During each increase or decrease, the direction of the force being transmitted is altered, and thus a predetermined amount of resilience or restoring force in the annular elastic component is required.
The annular elastic component of the present invention avoids and/or minimizes the above-discussed problems which may be present in the prior art and results in a particularly effective annular elastic component and flexible jaw coupling.